The present invention relates to an end surface polishing drive mechanism and to an end surface polishing machine having the drive mechanism for polishing the end surfaces of rod-shaped members such as an optical communications fiber elements.
Fiber elements (hereinafter xe2x80x9cfiberxe2x80x9d) are used in optical communication and are fixed in ferrules. The end surface of a ferrule and the end surface of a fiber are simultaneously polished so as to be smoothed into a mirrored finish after the fiber is adhered within a central hole of the ferrule that constitutes the main part of a connector. However, if the polished surfaces of the ferrule and the fiber are not perpendicular to a central axis of the ferrule, or if any of the polished surfaces are blemished in some manner, the precision of positioning opposing ferrules at optical connectors for connecting opposing ferrules together deteriorates and loss is therefore substantial. It is therefore necessary to give the polished surface of the ferrule including the optical fiber a high-precision polished finish.
This type of related optical fiber end surface polishing machine is disclosed in PCT International Publication Laid-open No. WO94/09944. This end surface polishing machine is provided with a fixing jig for fixing a plurality of ferrules to which optical fibers are fixed, The fixing jig is supported by a support mechanism, and a polisher provided with a polishing member for polishing the ferrules is located opposite the ferrules. The polisher is driven by a lapping motion mechanism capable of rotating the polisher both orbitally and about its own axis so that the end surfaces of the plurality of ferrules make contact with the polishing member in such a manner as to be subjected to the same pressure by the polishing member, with the end surfaces of the plurality of ferrules therefore being worked into a convex spherical surface.
A specific configuration for this machine is now described with reference to FIG. 6 and FIG. 7. As shown in FIG. 6 and FIG. 7, a central part of a first axial rotation transmitter 2 is fixed to the axis of rotation of a rotation motor 1 and a plurality of first coupling pins 3 are concentrically fixed to the first axial rotation transmitter 2 taking the center of rotation as center. Each first coupling pin 3 is coupled in a freely rotatable manner to a deviating part deviating by just a prescribed amount (e1) from each corresponding rotation transmitter 4, and first coupling pins 5 are fixed to the deviating part at each rotation transmitter 4. Each first coupling pin 5 is coupled in a freely rotating manner to a second axial rotation transmitter 6.
On the other hand, the central part of a driving gear 8 is fixed to a rotating shaft of an orbital rotation motor 7, and a driven gear 9 meshes with the driving gear 8. The driven gear 9 is fixed to the lower outer periphery of an orbital rotation transmission shaft 11, with a bearing 10 of a machine body fitting about the upper outer periphery of the orbital rotation transmission shaft 11. An axial rotation shaft 13 is fitted at the orbital rotation transmission shaft 11 in a freely rotatable manner at a position offset by a prescribed amount (e2) from the center of rotation, with the lower end of this axial rotation shaft 13 fixed to the central part of the second axial rotation transmitter 6.
With this axial rotation, the orbital rotation motor 7 causes the orbital rotation transmission shaft 11 to revolve about a Y axis via the driving gear 8 constituted by a single gear train and the driven gear 9. At this time, the center of the polisher 15 is at an axis Yxe2x80x2 offset by e2 from the Y axis, and this Yxe2x80x2 axis moves at a radius e2 about the axis Y. At this time, the axial rotation shaft 13 is present at the center of the orbital rotation transmission shaft 11, but the rotation transmitter 4 rotates about the first coupling pin 3 with the same phase as the revolution of the revolution transmission axis 11 because of the rotation transmitter 4 being located with the same deviation e1 as the deviation of the Y axis and the Yxe2x80x2 axis. The axial rotation of the orbital rotation transmission shaft 11 is therefore not limited regardless of whether the first axial rotation transmitter 2 stops or rotates.
On the other hand, with regards to rotational movement, the first axial rotation transmitter 2 is rotated by the rotation motor 1. However, the first coupling pin 3 is concentric with the first axial rotation transmitter 2, and passes through the same locus about the Y-axis. The axis of rotation of the axial rotation shaft 13 is offset from the axis of rotation of the first axial rotation transmitter 2 by e2, and the same number of rotations as for the first axial rotation transmitter 2 are transmitted to the axial rotation shaft 13 with the second coupling pin 5 concentric with the second axial rotation transmitter 6 maintaining an offset of e1.
A polishing member (not shown) is provided at the polisher 15 at the upper end of the axial rotation shaft 13 and rod-shaped members 16 of ferrules etc. to be polished by the end surface of the polishing member come into contact with the polishing member. The rod-shaped members 16 are detachably fixed to multiple fixing jigs 17 and the polisher 15 is pushed with a prescribed force by a pressing shaft 19. The fixing jigs 17 are prevented from rotating by a rotation prevention pin 20. A plurality of weights (not shown) are also arranged in such a manner that an arbitrary value can be selected for a weight to be applied to the support mechanism.
However, with the aforementioned related machine, there have been problems with regards to reducing the amount of space taken up by the machine, improving energy consumption, and improving ease of assembly because separate drive units are provided for axial rotation and for orbital rotation.
Further, the drive units have different torques for axial and orbital rotation. Therefore, when the plurality of rod-shaped members 16 fixed to the fixing jigs 17 are pushed when performing polishing, the rotation of the orbital rotation motor is uneven, the polishing locus becomes disturbed, and the desired polishing cannot be achieved.
In order to resolve the aforementioned problems, the present invention sets out to provide an end surface polishing drive mechanism and an end surface polishing machine that has a smaller footprint, consumes less energy, is easier to assemble, and in which work precision is improved without disturbing g the polishing locus.
In order to resolve the aforementioned problems the present invention provides, in a first aspect of the present invention, an end surface polishing drive mechanism for reciprocally rotating a polisher having a polishing member, pressing a rod-shaped member supported at a fixing jig onto the polishing member of the polisher and polishing the rod-shaped member. The drive mechanism comprises a rotating shaft, an orbital rotation shaft, orbital rotation shaft support means, drive means, a first gear, and a second gear. The rotating shaft has one end fixed to the polisher, and rotates both axially and orbitally together with the polisher. The orbital rotation shaft freely rotates at a position offset from the rotating shaft. The orbital rotation shaft support means supports the orbital rotation shaft in a freely rotating manner. The drive means rotatably drives the orbital rotation shaft. The first gear is fixed to, or close to, the other end of the rotating shaft. The second gear is provided along the locus of movement of the first gear and meshes with the first gear. Here, the rotating shaft rotates in conjunction with rotation of the orbital rotation shaft due to the drive means, and the rotating shaft rotates due to meshing of the first gear and the second gear.
In a second embodiment of the present invention, in addition to the first embodiment, the second gear is rotatably driven by the drive means at a different speed to the orbital rotation shaft.
In a third embodiment of the present invention, in addition to the first and second embodiments, the drive force of the drive means is transmitted to the orbital rotation shaft via a timing belt or a train of gears.
In another aspect, the present invention is directed to an end surface polishing machine having the end surface polishing drive mechanism according to the present invention.
According to the end surface polishing drive mechanism and the end surface polishing of the present invention, axial and orbital rotation can be performed by a single drive means and the machine therefore has a smaller footprint, consumes less power and is easier to assemble, while the load placed on the drive means does not change for rotating and revolving.